Dietary Sodium Reduction Fails to Reduce Clinical Heart Failure Events

Justin A. Ezekowitz, MBBCh MSc

New landmark findings from the SODIUM-HF trial reported that a dietary intervention to reduce sodium intake did not reduce clinical events in ambulatory patients with chronic heart failure.

In fact, strategies to reduce intake to less than 1500 mg daily were found to be no more effective than usual care in reducing the risk of hospitalization or emergency department visits due to cardiovascular causes or all-cause death.

“The dietary intervention in this study was feasible and effective in reducing sodium intake in patients with heart failure but did not result in changes in clinical outcomes, although small improvements were seen in quality of life and NYHA functional class,” wrote study author Justin A. Ezekowitz, MBBCh MSc, Canadian VIGOUR Centre, University of Alberta.

The late-breaking data were presented at The American College of Cardiology (ACC) 2022 Scientific Sessions in Washington, DC.

The Study of Dietary intervention under 100 mmol in Heart Failure (SODIUM-HF) trial was designed to test whether a reduction in dietary sodium reduced cardiovascular admission to the hospital, cardiovascular-related emergency department visits, and all-cause mortality within 12 months.

An international, open-label, randomized trial, participants were recruited from 26 sites in 6 countries (Australia, Canada, Chile, Colombia, Mexico, and New Zealand). Eligibility criteria included patients aged 18 years or older with chronic heart failure (NYHA functional class 2 - 3), and were receiving optimally tolerated guideline-directed medical therapy.

Within the low sodium diet group, a sodium target of less than 100 mmol (<1500 mg/day) was selected on the basis of epidemiological data, previous trial data, and practical limits of dietary intervention. The total intervention period was 12 months, while participants were additionally followed up for another 12 months.

A primary outcome was considered the composite of cardiovascular-related admission to hospital, cardiovascular-related emergency department visit, and all-cause death within 12 months after randomization.

From a study period between March 2014 - December 2020, 806 patients were randomly assigned to a low sodium diet (n = 397) or usual care (n = 409). Data show the median age was 67 years and 268 patients (33%) were women.

At baseline, the median sodium intake was 2286 mg/day for the low-sodium diet group and 2119 mg/day for the usual care group. At 12 months, the median sodium intake decreased in the usual care group to 2073 mg/day, equating a 4% decrease from baseline. In the low sodium group, the median sodium intake decreased to 1658 mg/day, representing a 28% decrease from baseline to 12 months.

Additionally, at 12 months, the primary outcome had occurred in 60 (15%) of 397 patients in the low sodium diet group and 70 (17%) of 409 in the usual care group (hazard ratio [HR] 0.89; 95% CI, 0.63 - 1.26; P = .53).

Cardiovascular-related emergency department visits occurred in 17 (4%) patients in the low sodium diet group and 15 (4%) patients in the usual care group (HR, 1.21; 95% CI, 0.60 - 2.41; P = .60). Investigators noted no safety events were reported in either the low sodium diet or usual care groups.

Despite not meeting the primary outcome, Ezekowitz noted longer term follow-up might or might not identify greater differences “because a dietary sodium reduction strategy might take a long time to accumulate benefit.”

The study, “Reduction of dietary sodium to less than 100 mmol in heart failure (SODIUM-HF): an international, open-label, randomised, controlled trial,” was presented at ACC 2022 and published in The Lancet.